Spectral decomposition of the all India landings of oil sardine, mackerel and Bombay duck

Abstract

All India annual landings of oil sardine, mackerel and Bombay duck from 1950
to 1992 were studied using spectral analysis to bring out the inherent
periodicity if any in these time series. The models fitted explained 88.3 % of
variations in oil sardine landings, 83.2 % in mackerel and 81.7 % in Bombay
duck. The major cyclic components identified are, 21 and 11 year cycles in both
oil sardine and mackerel landings, and 21, 11 and 7 year cycles in Bombay
duck landings. Projections of landings using the estimated spectral models
showed the years of peak landings as 2010-'ll for oil sardine, 2014 for mackerel
and 1999 for Bombay duck.